Rusted, corroded, or otherwise damaged ducts used for heating and air conditioning system applications are a known problem. When such damage is discovered, the ducts, or sections thereof, frequently have to be repaired or replaced. This is particularly true when this damage is discovered during an inspection related to the sale of real estate. This is a particular problem where the ducts are encased in a concrete slab. In such cases, the ducts can only be accessed by breaking away the section of slab, most often the floor of the property, in order to access the damaged duct section(s). This is a time consuming and costly process that is very invasive to the property in terms of disruption and debris. A need exists for a method and apparatus to repair a damaged section of duct without having to disrupt the property by replacing the section of duct.
U.S. Pat. No. 7,112,350, incorporated fully herein by reference, discloses a method and system for lining the interior of an air duct. The system disclosed in the '350 Patent, however, does not allow for the visual inspection of coating process. In addition, the system can get caught on joining sections of duct or other such irregularities requiring it to be pulled with great force such that upon release, the system jumps down the section of duct leaving a poorly, or even uncoated, section of duct. A need also exists for a system and method for coating ducts which allows for the visual inspection of the duct during application of the coating material and which is capable of traveling down the length of duct without catching onto seams, turns, or other obstructions in the duct.